When tail light switch is turned on, tail light relay on fuse block behind left side kick panel energizes and contacts close. You will hear a click.

There will be 12V at:
1) Tail light fuse,
2) Green wire going to tail lights,
3) Green wire going to dash cluster.
4) Pin A of backlight bulbs.


Point B of dimmer connector (harness side)with at least one good backlight bulb installed:
Close to 12V with dimmer disconnected or with dimmer at dimmest position.
Zero V or close to zero V when dimmer at brightest position.

Connecting "B" of harness side of dimmer directly to bare, shiny metal of body (ground) will turn dash backlights on.


Schematic and Voltage Test Points Below:


LOCATION OF PARTS: